Antispasmodics such as alverine citrate, mebeverine hydrochloride or peppermint oil can be used as required, alongside lifestyle and dietary advice. While generally considered safe, they only benefit a relatively small number of patients. Loperamide is the first-choice anti-motility agent in IBS.^1,2,21

Laxatives should be considered for IBS with constipation, but avoid lactulose as this may cause bloating. Bulk fibre and senna may worsen pain in some people.^1,2

Linaclotide is indicated for moderate to severe IBS with constipation, but NICE advises that it should only be used if other laxatives have not helped, and constipation has been an issue for 12 months. People taking linaclotide should have a follow up after three months.^2,21

If antispasmodics, loperamide or laxatives have not helped, a second-line option may be a tricyclic antidepressant. The starting dose is 5mg to 10mg amitriptyline or equivalent, titrated up to 30mg if necessary. If a tricyclic is not effective, a selective serotonin reuptake inhibitor (SSRI) may be considered, but tricyclics and SSRIs are not licensed for this use.²

If pharmacological approaches have not been successful, NICE recommends referral after 12 months for cognitive behavioural therapy CBT, hypnotherapy and/or psychological therapy.²